What more can I say?
There are two more important situations to note, that occur during this, the Individuolect period. One has to do with fluency, and the other with phoneme pronunciation.
Fluency: From around two to seven years of age, the child is engaged in an activity that puts many college students in fear--learning a new language. All things being equal, it is a more daunting task for the child because they not only have to learn the phonemes, morphemes, syntax and pragmatics, but they also have to learn the concepts that go with the symbols. In addition, they have not had much time to sharpen their study skills.
With the help of Chomsky's Language Acquisition Device, and many other biological aids (as outlined by Eric Lenneberg in his book, the Biological Foundations of Speech), however, the child prevails and becomes a linguistic communicator in fairly short order.
We almost forget that young children are still beginners at the language game.